Dirk Nowitzki threw out the first pitch before the Rangers' game against the Mets on June 24. Jim Cowsert/US Presswire

The Rangers confirmed that they sent Nowitzki's name as part of a list of first-pitch possibilities and that MLB decided not to use him. The club did not say why he was rejected.

Unlike regular-season games, all first-pitch assignments in the World Series have to be approved from a list of candidates by the league office.

Sources told ESPNDallas.com that -- with the NBA in the midst of a lockout that has spanned 111 days -- at least some hesitation stems from the idea that MLB executives want to stand behind their basketball counterparts and have notified the Rangers that they won't bestow first-pitch honors on an NBA player.

Major League Baseball insists that the NBA's labor unrest had no impact on Nowitzki not being selected to throw out the first pitch.

"MLB absolutely denies that any part in selecting the first ball pitcher had anything to do with the current labor situation in the NBA," MLB spokesman Pat Courtney said. "You want the club's input in what makes sense for them and then we talk about what makes sense for the team and a good broad-base national appeal.

"It's a nice problem to have that you get a list of 10 or 15 names and you work your way through them. We know Nowitzki's been at the games, and that's wonderful. We're glad he's there."

Nowitzki declined comment Wednesday, but a statement from his Twitter account indicated that he would maintain support for the Rangers during the World Series:

"Thanks every1 on the support regarding first pitch. Its ok.Mlb is too old school. I will still be there to support our boys. Let's get game1"

Nowitzki, who was the MVP of the NBA Finals, is a diehard Rangers fan who says he watches "every playoff game" and attended Game 6 of the American League Championship Series.

He also threw out the first pitch before the Rangers' game June 25 against the New York Mets, roughly two weeks after leading the Mavericks past the Miami Heat for the first championship in franchise history.

"[Nowitzki] was a consideration and it's definitely not happening," one source with knowledge of the Rangers' thinking told ESPNDallas.com.

The NBA lockout began July 1. On July 22, Mavs teammate Jason Terry threw out the first pitch before the Rangers' game against the Toronto Blue Jays.

Rangers CEO and Hall of Famer Nolan Ryan, Hall of Fame pitcher Fergie Jenkins and former presidents George H.W. Bush and George W. Bush threw out first pitches during last year's World Series games at Rangers Ballpark in Arlington.

Marc Stein covers the NBA for ESPN.com. Richard Durrett of ESPNDallas.com contributed to this report.